DEVICE AND METHOD FOR READING FINGERPRINT

摘要

PURPOSE: To realize a fingerprint reader and its method capable of clearly reading the fingerprint image even of a dry finger. CONSTITUTION: Since the back face side of a finger placed on a sensor surface SF of a photosensor array SA is irradiated with light of an upper illumination light source FL, the degree of scattering of light that transmits the finger becomes different between the ridges and valleys of a fingerprint and is hardly affected by the degree of contact to the sensor surface SF. Because of this, a fingerprint image corresponding to the ridges and valleys of the fingerprint can be clearly read with the photosensor array SA even in the case finger skin is dry enough to make it difficult to bring the finer into close contact with the sensor surface SF of the photosensor array SA due to the minute irregularities of the fingerprint.